Interferential current stimulation during dental facial treatment improves masticatory function

Interferential current transcutaneous stimulation (IW) has been reported to influence swallowing-related sensorimotor function, although its immediate effects on mastication remain unclear. In a randomized, sham-controlled crossover study, we examined whether IW stimulation applied over the masseter region is associated with immediate improvements in masticatory performance. The primary endpoint was glucose elution from a standardized gummy jelly, an indicator of masticatory and occlusal function; the secondary endpoint was a 0-100 mm VAS of chewing ease. Mixed-effects modeling adjusted for period and sequence. IW produced immediate, within-session gains in occlusal function: glucose elution increased after IW (mean difference + 31.5 mg/dL, p < 0.001) but decreased with sham (- 19.8 mg/dL, p = 0.0019). VAS improved within both treatments, with a larger median gain under IW, and the mixed-effects model favored IW over sham. Although this study does not directly assess neural circuits, the observed pattern is consistent with peripheral sensory influences on masticatory output. Expectancy effects and other nonspecific contributors cannot be fully excluded and should be addressed in future studies using active control conditions and direct physiological measures. IW may offer a rapid, noninvasive adjunct to oral rehabilitation; confirmatory trials should incorporate direct force/EMG, jaw kinematics, and salivary measures, and assess durability and clinical outcomes.Trial registration: UMIN-CTR UMIN000058249 (registered 2025-07-01). Direct link: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000066586 .